The present invention relates to a lift apparatus for lifting a manhole cover. More particularly, the present invention relates to a manually operated manhole cover engaging tool.
Utility covers, also known as "manhole" covers, are frequently used to cap entrances to subsurface enclosures. For example, manhole covers are often used to cover the openings to sanitary and storm sewers, subsurface telephone cable and communication line junction boxes, electrical enclosures, and enclosures providing access to subterranean pipes.
Most manhole covers are constructed of thick metal, commonly iron, and are often very heavy usually weighing over 50 pounds. The great strength and weight of manhole covers serve a number of purposes, including preventing unauthorized access to the enclosure by children or other persons, preventing inadvertent movement and displacement of the manhole cover by vehicles, and providing a solid base for people and transportation equipment traveling over the manhole.
However, the weight of manhole covers also poses a significant problem to their use because they are difficult and sometimes hazardous to remove. The fact that manhole covers are usually heavy, combined with the fact that they are usually positioned at ground level, means that a worker trying to remove a manhole cover usually attempts to lift the heavy manhole cover from a bent-over position. This bent-over lifting position can lead to back injuries, which result in pain and suffering. These injuries also cause lost productivity and income for employees and employers.
A conventional method of removing manhole covers is to pry the edge of the manhole cover upward with a pick, and then rotate the cover away from the opening with either the pick or another tool, such as a shovel or pry-bar. Conventional removal methods often require that the worker removing the cover grab the edge of the cover. Grabbing a manhole cover can be very hazardous, because workers risk crushing their fingers under the weight of the cover or severely pinching their fingers between the cover and the rim of the manhole. Also, use of the hands usually means that the worker is bent over the manhole, providing additional concern about back injury.
Conventional apparatuses and methods of opening manholes also pose the problem that the worker must be relatively close to the manhole while removing the cover. The proximity of the worker to the manhole can be problematic because manholes are often very deep, and falling into an open manhole can cause severe injuries or even death. Under some circumstances, such as overflowing sewers or ruptured water mains, water may be leaking out of the top of the manhole, creating a slippery, wet surface proximate the manhole opening. This slippery surface can be especially troubling during winter when ice forms proximate the manhole. Therefore, it is desirable for a manhole opener to permit the removal of the manhole cover while the worker is a safe distance from the opening.
A further problem associated with removing manhole covers is that not all manhole covers can be removed in the same manner. Some covers have a small round opening in the middle of the cover. Other manhole covers have a slot or depression on the outer edge of the cover, while still others have one or more slots, holes, or depressions positioned between the edge and the center of the manhole. These various configurations can be a challenge to open, and may require specialized tools for each manhole.
Another problem associated with removing manhole covers is the difficulty in replacing the manhole cover. Under a conventional method, a pick is used to pry up the edge of the cover, which is then manually flipped up onto its side, rolled over to the opening, and then slowly rotated into place. This is a tedious and somewhat difficult task because of the great weight of the cover. Also, two people are often required to easily replace the manhole cover, the first to pry the edge off the ground, and the second to flip the manhole cover into a vertical position and roll it into place.
Accordingly, there is a need for an apparatus and method for safely, easily, and efficiently removing and replacing a manhole cover. Even further, there is a need for an apparatus which permits one person to remove and replace a manhole cover with a minimum of stress and danger, and a reduced risk of injuries to hands, feet, and backs.